Daptomycin-producing Streptomyces strain and use thereof

Abstract

The present invention provides a novel daptomycin-producing Streptomyces strain and use thereof, the strain is a subspecies of streptomyces griseus, named Streptomyces griseus L340, and the preservation number is CGMCC17921. The genetic character and fermentation unit of the strain provided by the present invention are relatively stable, the culture and fermentation conditions are suitable for industrial production of daptomycin, and the interference of pigment in later separation and purification is eliminated. The secondary metabolite daptomycin is obtained through fermentation of the Streptomyces provided by the present invention, which has the advantages of no interference of pigment accumulation, cleaner metabolic spectrum and thus is obviously superior in later separation and purification.

What is claimed is: 
     
       1. A novel daptomycin-producing  Streptomyces  strain, wherein the  Streptomyces  strain is classified and named as  Streptomyces griseus  L340 preserved in China General Microbiological Culture Collection Center with a preservation date of Jun. 12, 2019 and a preservation number of CGMCC No. 17921, and the strain is kept in a media with a buffer to maintain the pH 5-11. 
     
     
       2. A method for culturing the Streptomyces strain according to  claim 1 , comprising the following steps:
 (1) solid culture: inoculating the strain on an agarslantculture-medium, and culturing in an incubator at 30° C. for 5-8 days; and 
 (2) liquid culture: cutting spores from the agarslantculture-medium and inoculating into a seed broth, culturing on a shaker with a rotation speed of 250 rpm at 30° C. for 36 hours, then inoculating a transfer amount of 4% into a fermentation medium, and culturing on a shaker with a rotation speed of 250 rpm at 30° C. for 4-6 days. 
 
     
     
       3. The method according to  claim 2 , wherein the agarslantculture-medium in the step (1) is a R 5  medium, each liter of medium which contains 103 g of sucrose, 10 g of glucose, 5 g of yeast extract, 0.1 g of casein hydrolysate, 0.25 g of K 2 SO 4 , 10.12 g of MgCl 2 ·6H 2 O, 2 mL of a trace element solution, 5.73 g of TES buffer, and 0.3 g of proline, which are diluted by water to a volume of 1 L, and 22 g of agar is added to a solid medium;
 in the step (2), the seed broth is a Trypticase Soy Broth medium: TSB 2%, PEG 6000 5%, which are diluted by water to a volume of 1 L, wherein the percentages are percentages by mass; and 
 the fermentation medium in the step (2) is a yeast malt medium: 0.3% yeast extract, 0.3% malt extract, 0.5% tryptone, and 4% glucose, which are diluted to a volume of 1 L. 
 
     
     
       4. A production method of daptomycin using the  Streptomyces griseus  L340 according to  claim 1 , comprising the following steps:
 (1) cutting spores from an agarslantculture-medium, inoculating the spores into a seed broth, and culturing on a shaker with a rotation speed of 250 rpm at 30° C. for 36 hours until a bacterial liquid is sticky and granular; 
 (2) harvesting 4% by volume of the bacterial liquid from the seed broth, inoculating into the fermentation medium, and culturing on a shaker with a rotation speed of 250 rpm at 30° C.; and after 48 hours, feeding decanoic acid in 0.1% by volume of the fermentation medium every 12 hours; 
 (3) after 144 hours, treating the fermentation broth with methanol of equal volume, and subjecting a supernatant obtained after centrifugation to subsequent separation and purification to obtain the daptomycin. 
 
     
     
       5. The production method according to  claim 4 , wherein, definitions of the agarslantculture-medium, the seed broth and the fermentation medium are the same as in  claim 3 .